High-efficiency 50 W burst-mode hundred picosecond green laser

Abstract

We report high-energy, high-efficiency second harmonic generation in a near-infrared all-solid-state burst-mode picosecond laser at a repetition rate of 1 kHz with four pulses per burst using a type-I noncritical phase-matching lithium triborate crystal. The pulses in each burst have the same time delay ( ${\sim}1~\text{ns}$ ), the same pulse duration ( ${\sim}100~\text{ps}$ ) and different relative amplitudes that can be adjusted separately. A mode-locked beam from a semiconductor saturable absorber mirror is pulse-stretched, split into seed pulses and injected into a Nd:YAG regenerative amplifier. After the beam is reshaped by aspheric lenses, a two-stage master oscillator power amplifier and 4f imaging systems are applied to obtain a high power of ${\sim}100~\text{W}$ . The 532 nm green laser has a maximum conversion efficiency of 68%, an average power of up to 50 W and a beam quality factor $M^{2}$ of 3.5.

8 mJ 355 nm 1 kHz burst-mode picosecond laser systems

“…The 1064 nm pump source comprises four parts, namely mode locking, pulse broadening, beam-split combination, and regenerative amplification; specific device descriptions for these parts can be referred to in our previous work [11,12]. As shown in figure 2, the output power, repetition frequency, single-pulse width, subpulse interval, number of subpulses in the pulse envelope, and beam quality were 8.…”

1.2 kW all-fiber narrow-linewidth picosecond MOPA system

“…A kilowatt-scale ps system with tens of μJ energy at MHz repetition frequency may achieve a compromise between the harsh thermal effects of continuous wave lasers and the low processing speed of fs lasers [ 13 , 14 ] . Moreover, a high-power infrared ps laser is the ideal pump source of second harmonic generation for the urgently needed visible pulse [ 15 ] . Meanwhile, a ps source with narrow spectral widths can mitigate the temporal walk-off effect during the harmonic conversion process [ 16 ] and enable a high spectral resolution in nonlinear micro-spectroscopic imaging applications, such as coherent anti-Stokes Raman scattering spectroscopy [ 17 , 18 ] .…”

4 mJ Rectangular- Envelope GHz-Adjustable Burst-Mode Fiber-Bulk Hybrid Laser and Second-Harmonic Generation

“…High peak power and high pulse energy burst-mode pulse lasers distinctively contain a bunch of high repetition rate pulses with durations ranging from the ultrafast regime (<10 ps) to several nanoseconds and possess a great number of applications [1][2][3][4][5][6][7][8][9]. For example, ultrafast burst-mode lasers have been demonstrated more efficient and accurate in cooled ablation material processing [1][2][3].…”

“…[4][5][6][7]. In addition, a group of picoseconds pulses with adequate energy could improve the ranging precision in LIDAR application [8,9] and realize the simultaneous measurement of multi-physical-parameters in turbulent flows [10,11].…”